Pakistani authorities are racing against time to deliver relief supplies to the country's quake-affected north west amid forecasts of heavy rain and snowfall there for the next week.

Asghar Nawaz, director-general at the National Disaster Management Authority, said relief workers were using trucks, eight helicopters and a military plane to provide aid including blankets, tents and food.

"The bad weather can delay the relief activities," he told reporters in the capital Islamabad.

Mr Nawaz was speaking after visiting towns and villages in north-western Khyber Pakhtunkhwa province that were worst affected by Monday's magnitude-7.5 earthquake.

The tremor was centred in neighbouring Afghanistan's Badakhshan province which borders Pakistan, Tajikistan and China - but caused extensive damage in Pakistan's north west, specifically in the Swat Valley and the towns of Chitral and Shangla in Khyber Pakhtunkhwa.

The quake killed at least 396 people - 272 in Pakistan, 121 in Afghanistan and three on the Indian side of the disputed Kashmir region. Authorities in Khyber Pakhtunkhwa said 62 women and 57 children were among 223 killed in the province.

It damaged 35,492 homes in Pakistan, where government has promised to help people rebuild their homes. Mr Nawaz said relief workers are also transporting aid to the country's quake-hit tribal regions bordering Afghanistan.